used working model Thermo Finnpipette Labsystems pipet multichannel (8 channel) with tips ejector 0.5 ul-10 ul. The pipettors sold have been used only with non-radioactive and non-biohazardous materials. Also, all pipettors have been tested to work properly- I have measured the aliquottes on a Mettler scale. If you are not satisfied, you can return the product within 5 days for a full refund excluding shipping expenses.Lot gar1stshleftwhite